Direct-write X-ray lithography using a hard X-ray Fresnel zone plate.

Results are reported of direct-write X-ray lithography using a hard X-ray beam focused by a Fresnel zone plate with an outermost zone width of 40 nm. An X-ray beam at 7.5 keV focused to a nano-spot was employed to write arbitrary patterns on a photoresist thin film with a resolution better than 25 nm. The resulting pattern dimension depended significantly on the kind of underlying substrate, which was attributed to the lateral spread of electrons generated during X-ray irradiation. The proximity effect originated from the diffuse scattering near the focus and electron blur was also observed, which led to an increase in pattern dimension. Since focusing hard X-rays to below a 10 nm spot is currently available, the direct-write hard X-ray lithography developed in this work has the potential to be a promising future lithographic method.

Coherent X-ray scattering beamline at port 9C of Pohang Light Source II.

The coherent X-ray scattering beamline at the 9C port of the upgraded Pohang Light Source (PLS-II) at Pohang Accelerator Laboratory in Korea is introduced. This beamline provides X-rays of 5-20 keV, and targets coherent X-ray experiments such as coherent diffraction imaging and X-ray photon correlation spectroscopy. The main parameters of the beamline are summarized, and some preliminary experimental results are described.

Demonstration of feasibility of X-ray free electron laser studies of dynamics of nanoparticles in entangled polymer melts.

The recent advent of hard x-ray free electron lasers (XFELs) opens new areas of science due to their exceptional brightness, coherence, and time structure. In principle, such sources enable studies of dynamics of condensed matter systems over times ranging from femtoseconds to seconds. However, the studies of "slow" dynamics in polymeric materials still remain in question due to the characteristics of the XFEL beam and concerns about sample damage. Here we demonstrate the feasibility of measuring the relaxation dynamics of gold nanoparticles suspended in polymer melts using X-ray photon correlation spectroscopy (XPCS), while also monitoring eventual X-ray induced damage. In spite of inherently large pulse-to-pulse intensity and position variations of the XFEL beam, measurements can be realized at slow time scales. The X-ray induced damage and heating are less than initially expected for soft matter materials.